There are two main kinds. One has a reusable firing mechanism in which a disposable lancet is loaded, and after use the lancet has to be unloaded and safely disposed of. The other kind has the lancet as part of a trigger device, the whole of which is thrown away after a single use. These are small and simple, to be economic, but nevertheless they have hitherto generally required several parts, separately moulded or otherwise fabricated, to be assembled together. The less the number of parts and the fewer the assembly operations the better for such throwaway items.